Calcining-furnace.



nu. 633,777. Patented sept; .26, |399.

C. M. ALLEN.-

CALCINING FURNACE.

(Appumion mea my 27, 189s.; (No Model.) 5 Sheets-Shea? l,

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Patented Sept. 26, |8992` C. M. ALLEN.

CALCINING FURNACE.

(Application led July 27, 189B.)

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(No Model.)

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No. 633,777. Patented Sept. 26, 1899.

c. m. ALLEN. CALGINING FURNACE.

' (Application led .Tuly 27, 1898.) (No Model.) 5 Sheets-Sheet 3.

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no. 633,777. Patented sep'f. 2s, |899.

7 c. M. ALLEN.

CALGIMING FUBNAGE.

(Application med .my 27, 189s., (No Modal.) 5 Sheets-Sheet 4.

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No. 633,777. Patented Sept. 26,' |899.

C. M. ALLE-N.

CALCINING FURNACE.

(Application filed July 27, 1898.) (No Model.)

5 Sheets-Sheet 5,

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UNITED STATES PATENT OFFICE.

CHARLES M. ALLEN, OF BASIN, MONTANA.

CALCINING-FURNACE.

SPECIFICATION forming part of Letters Patent No. 633,777, dated September 26, 1899.

Application filed July Z7, 1898. Serial No. 686,977. No model.) i

1U @Z LU/wm, it may concern.-

Be it known that I, CHARLES MAURICE AL- LEN, of Basin, in the county of Jefferson and State of Montana, have invented a new and Improved Calcining-Furnace, of which the Vfollowing is a full, clear, and exact description.

The object of the invention is to provide certain new and useful improvements in calcining-furnaces whereby the material under treatment is thoroughly caleined in a comparatively short time and very economically as to the use of fuel and whereby the material is relieved of its moisture previous toits entrance into the hearth to prevent the formation of sulfuric acid, so destructive to the hearth and the traveling and stirring devices as experienced in furnaces heretofore constructed.

The invention consists of novel features and parts and combinations ofthe same, as will be fully described hereinafter and then pointed out in the claims.

A practical embodiment of my invention is represented in the accompanying drawings, forming a part of this specification, in which similar characters of reference indicate eorresponding parts in all the views.

Figure 1 is a sectional elevation of the improved furnace. Fig. 2 is an enlarged longitudinal elevation ofthe rear end of the same. Fig. 3 is a sectional plan view of the same. Fig. 4 is an enlarged sectional eleva-tion of the forward end of the lower hearth. Fig. 5 is an enlarged transverse section of the improvement on the line 5 5 in Fig. 1. Fig. (i is an enlarged plan view of the stirring devices. Fig. 7 isa transverse section of the extension for the lower hearth with the receiving-floor for the material, the section being through one of the supporting-arches on the line 7 7 in Figs. 1 and 9. Fig. 8 is a similar view of the extension for the lower hearth, the section being on the line 8 8 in Fig. 1. Fig. 9 is a sectional side elevation of the receiving or drying floor on the lower hearth extension, the section being on the line D 9 in Fig. 7. Fig. 10 is an enlarged transverse section of the improvement, on the line 10 10 in Fig. 1, and showing the lire-box for the lower hearth. Fig. 11 is a similar view of the same on the line 11 11 in Fig. 1 and showing the fire-box for the upper hearth. Fig. 12 is an enlarged sectional side eleVat-ion of the shoe carried by the stirring device for opening the hearth-doors. Fig. 13 is an edge View of the same. Fig. 14 is an enlarged plan View of the rail. Fig. 15 is a side elevation of the same. Fig. 1G is a plan view of one of the rail-chairs. Fig. 17 is a side elevation ofthe same, and Fig. 18 is a cross-section of the rail and chair.

The calcining-furnace is built of the usual masonry and with an upper or entrance hearth A and a lower or discharge hearth B, both connected with each other at their rear ends by a drop-opening C, which allows the material under treatment andV moved rearward in the hearth A in the direct-ion of the arrow a to finally drop through said opening into the lower hearth B to be moved forward therein in the inverse direct-ion of the arrow a'. The material in the hearths A and B is agitated and moved therein in the direction described by suitable continuous-stirring devices D, passing through both hearths in the direction of the arrows, each stirring device being provided with angular plows D', (see Fig. 6,) mounted on a suitable carriage D2, adapted to travel on rails E, held in the bottoms of the hearths, as hereinafter more fully described, said carriages being' attached to an endless chain D3, passing over wheels D5 and D6, located at the rear and front ends of the lower hearth B, as is plainly illustrated in Figs. 1, 2, 3, and 4, said wheels being secured on shafts D7, journaled in suitable bearings and connected at their outer ends by a pulley D8 and a belt to other machinery for imparting a rotary motion to the shafts to cause the wheels D5 DG to impart a traveling motion to the chain D3, and thereby move the stirring devices through the hearths. The plows D of successive stirring devices are preferably arranged in opposite directions relatively to each other, as will be readily understood by reference to Fig. G.

The forward end of the lower hearth B is formed with an extension B", extending beyond the front end of the upper hearth A, (see Fig. 1,) and part of tbe top of this eX- tension forms a receiving and drying floor B2 for the material under treatment, said material being discharged upon the forward end IOO of the floor by a traveling belt F, receiving ing or hood H, secured to the ends of the the material from a mechanical feeder F of i hearths and inclosing the wheel D5 and the any approved construction.

The floor B2 is preferably formed of castiron plates B3, having side flanges B1 (see Figs. 7 and.9) to prevent the material from falling over the sides of the floor when moved forward by the action of the stirring devices. The floor B2 is on a level and in alinement with the bottom of the hearth A, and the stirring devices in passing over said floor move the material rearward and into the upper hearth A. Said stirringdevices beingexposed to the open air are thus cooled while passing over said floor and over the outer portion of the roof of the extension B', and which outer portion is not used as a drying-floor for the ore. The eXtreme outer portion of the top of the extension B' is simply provided with supports for the rails E, but not with a floor. (See Fig. 8.)

Part of the top 0f the extension-hearth B (see Figs. 7 and 9) and the plates B2 are directly and highly heated by the heat of the extension-hearth, and said plates are capable of imparting this heat to the ore on the floor, and consequently the. ore moved over the fioor B2 by the stirring devices is almost completely relieved of its moisture before the ore enters the upper hearth and before said moisture can combine with the sulfur fumes producedin the hearth to form sulfuric acid, the corrosive action of Awhich is so detrimental to the life of the furnace.

The floor B2 is of considerable length, and in practice it requires several hours for the ore to travel from the outer end of the floor B2 to the entrance of the upper hearth A, and hence the heat from the floor B2 has sufficient time to expel the moisture in the ore.

The plates B3 forming the floor B2 are riveted or otherwise fastened to transverse angle-irons B5, set in chairs B6, supported on transverse arches, spaced apart, as indicated in Fig. 9, the outer ends of theangle-irons being secured to the binding-rods for the masonry of the furnace. Thus by the arrangement described the licor-plates B3 are directly subjected to the heat emanating from the burning material passing through the lower hearth B in the inverse direction of the arrow a'.

The forward end of the upper hearth A is provided with a suitable fire-box G, (see Figs. 1 and 11,) and a similar tire-box G', (see Figs. 1 and 10,) leads to the lower hearth B, somewhat in front of the drop-opening C; but other additional fire-boxes may be located in the masonry at intervals throughout the length of the hearths A and B, and the latter may also be provided at intervals with suitable doors G2, as indicated in Figs. 2, 3, et, and 5.

In order to make the hearths A and B practically continuous, to avoid loss of heat, and to prevent air from entering at the rear ends of the heart-hs A and B, I provide a casstirring devices passing over the same in their passage from the upper hearth A to the lower hearth B. (See Figs. 1 and 2.) The rear ends of the hearths A and B are in addition normally closed by self-closing doors I I', and similar doorsl2 13 normally close the front ends of .the hearths A B, respectively, and all of said doors are automatically opened in advance of an approaching stirring device by shoes 14, carried on the carriage of said device, as is plainly shown in Figs.6, 12, and 13.

The forward end of the lower hearth B is provided at its bottom with an outlet B3, leading to the throat J of a large storage-hopper J, connected by a hot-air flue with the main stack to permit escape of the gases passing;` with the material from the lower hearth B into said hopper. The latter is built directly over a reverberatory smelting-furnace, of any approved construction but not shown, so that the calcined material accumulating in the storage-hopper from the calcining-furnace may be directly discharged into the smeltingfurnace, according to the requirements of the latter.

From the foregoing it isevident that as the two hearths A and B are practically continuous the fire travels through the material in the direction indicated by the arrows in Fig. 1 from the upper hearth to the lower hearth withoutloss of heat to insure a proper calcination of the material without a great expendit'ure of fuel in the tire-boxes. It will further be seen that by the arrangement described the air that enters the front end of the upper heart-h A by way of its fire-box G travels to the back of the hearth and then through the opening C, then descends into the lower hearth and travels forward therein to finally reach the-stack connection by way of the hopper, as previously explained, and by this arrangement the heat travels through the ore and isV introduced at the point where theore is comparatively cold, and the heat is carried through the ore during the entire operation of calcining. As no outer cold air passes into the lower hearth and its extension B', it is evident that the said extension and the drying-floor B2, forming part of the roof for the extension, do not become cooled, and consequently a proper drying of the ore takes place on said floor, and a final proper calcining of the ore is carried on in the extension previous to the discharge of the ore into the throat J of the hopper J.

The heat from the burning material traveling in the extension B ofthe lower hearth heats the iioor B2 sufficiently to properly dry the material coming from the mechanical feeder F', so that very little, if any, sulfuric acid (HZSOQ is produced in the hearth A, as is so frequently the case in calcining-furnaces, as heretofore constructed.

It is well known that sulfuric acid is very destructive to the material ofwhich the hearth IOO IIO

is built, and consequently, as very little, if l hearth beneath it, leavingouecnd of the roof any, sulfuric acid is generated in the hearth, t of the lower hearth exposed to form a dryingthe life of the hearth is greatly lengthened. The extension B of the lower hearth gives considerable length for the material to travel in and on its top it heats and dries the fresh ore and allows the stirring devices to cool after leaving the forward end of the lower hearth B and before reentering the upper hearth A. Should any outside air pass into the forward end of the upper hearth A, it

passes through the lire emanating from the fire-box G, and thus becomes heated and useful in the furnace, and any air passing into the forward end of the lower hearth goes directly into the throat J of the hopper .I and to the stack, so that said outer air is prevented from lowering the temperature of the lower heart-h, and hence more effective calcining takes place in a comparatively short time and with the least amount of fuel.

In furnaces as heretofore constructed the rails for the carriage of the stirring devices usually buckle and warp from the intense heat within the hearth, and in order to prevent this I provide the following construction: The rails E are bolted to vertically-disposed lugs E2 on the chairs E', made in the form of flat plates, bolted to or set on the bottom plates, carrying the brick bottom for the hearth, and the brick bottom covers the chair, as is plainly shown in Figs. 7 and S. The bolt-holes E in the rails E (see Eig. l5) are slotted longitudinally to allow expansion and contraction of the rails exposed to the heat in the hearth without straining the chairs. The ends EAl of the rails E are beveled in opposite directions, as is plainly shown in Figs. let and 15, to form cutting edges, so that when the rails expand bythe heat they can readily cut their way through the brick floor and the ore on the floor. The upper portions of the ends E1L are formed with beveled projections E5, so that adjacent rails overlap by their projections E5 to render the track continuous, it being understood that the ends E* of adjacent rails are set about an inch apart when laying the-track to make provision for expansion when the furnace is heated up. The ends E6 of the chair-plates and the ends E7 of the lugs E2 are also beveled to form cutting edges, so that when the chairs expand the edges readily cut their way in the brick bottom without bulging the plates or displacing the brick.

From the foregoing it will be seen that the rails can expand and contract without danger of bulging and without affecting thereby the chairs, and the latter expand and contract irrespective of the rails and without danger of warping and heaving the brick bottom of the hearth.

Having thus fully described my invention, I claim as new and desire to secure by Letters Patentl. A calcining-furnace provided with a plurality of hearths located one above the other, the uppermost hearth being shorter than the floor leading to the entrance of the upper hearth, said drying-floor being capable of freely taking up the high heat emanating from the burning material traveling through the lower hearth, and the said floor being also capable of imparting such heat to the material discharged upon the drying-floor, to expel the moisture from said material during its travel over said floor and previous to its entrance into the upper hearth at or near the entrance ends thereof, inlets for the products ot' combustion to the said hearths at or near the entrance ends thereof and an outlet for the products of combustion at the discharge end of th.e lower hearth.

A calcining-furnace provided with aplurality of hearths located one above the other, the uppermost hearth being shorter than the hearth beneath it, leaving one end of the roof of the lower hearth exposed to form a drying-Hoor leading to the entrance end of the upper hearth, the other end of the upper hearth being connected with the unexposed end of the lower hearth which is provided with a discharge at or near the end of its exposed portion, the material to be treated traveling over said drying-floor and through the upper hearth in one direction, to then travel in the reverse direction in the lower hearth, said floor being capable of freely taking up the high heat emanating from the outwardlymoving material in the exposed portion of the lower hearth, said floor being also capable of imparting such heat to the material traveling over it, to expel the moisture previous to the material passing into the upperl hearth at or near the entrance ends thereof, means for traversing the material over the said drying-floor, inlets for the products of combustion to the said hearths at or near the entra-nce ends thereof and an outlet for the products of combustion at the discharge end of the lower hearth.

3. Acalcining-furnace provided with aplurality of hearths located one above the other, the uppermost hearth being shorter than the hearth beneath it, leaving one end of the roof of the lower hearth exposed to form a dryingfloor leading to the entrance end of the upper hearth, the other end of the upper hearth being connected with the unexposed end of the lower hearth which is provided with a discharge at or near the end of its exposed portion, the material to be treated traveling over said dryingdoor and through the upper hearth in one direction, to then travel in the reverse direction in the lower hearth, said floor being capable of freely taking up the high heat emanating from the outwardlymoving material in the exposed portion of the lower hearth, said door being also capable of imparting such heat to the material passing into the upper hearth, feed devices for discharging the material to be calcined on the outer end of the said drying-floor,

whereby the material is heated in the open air, to be dried for the purpose described, plowing or agitating devices, means for moving the said devices through the hearths at or near the entrance ends thereof from one to the other, inlets for the products of combustion to the said hearths at ornear the entrance ends thereof and an outlet for the products of combustion at the discharge end of the lowermost hearth.

4. A calcining-furnace provided with a plurality of hearths located one above the other, the uppermost hearth being shorter than the hearth beneath it, leaving one end of the roof of the lower hearth exposed to form adryingoor leading to the entrance end of the upper hearth, the other end of the upper hearth being connected with the unexposed end of the lower hearth which is provided with a discharge at or near the end of its exposed portion, the material to be treated traveling over said drying-floor and through the upper hearth in one direction, to then travel in the reverse direction in the lower hearth, said door being capable of freely taking up the high heat ernanating from the outwardly-moving material in the exposedportion of the lower hearth, said iioor being also capable of imparting such heat to the material passing into the upper hearth, feed devices for discharging the material to be calcined on the outer end of the said drying-Hoor, whereby the material is heated in the open air, to be dried for the purpose described,plowing or agitating devices, means for moving said devices through the hearths from one to the other, a receptacle at the discharge end of the lower hearth, to receive the calcined material and the gases from the lower hearth, inlets for the products of combustion to the said hearths at or near theentrance ends thereof and an outlet for the products of combustion at thedischarge end of the lowermost hearth.

5. A calcining-furnace provided with a plurality of hearths located one above the other,

said material is primarily heated in the open air to be dried, plowing or agitating devices, means for moving the said devices through the hearth from one to the other, a hood for closing the outer ends of the hearths, to make the same practically continuous, a return mechanism for said plowing or agitating devices and contained in said hood, inlets for the products of combustion to the said hearths at or near the entrance ends thereof and an outlet for the products of combustion at the discharge end of the lowerinost hearth.

G. A calcining-furnace provided with a plurality of hearths located one above the other, the uppermost hearth being shorter than the hearth beneath it, leaving one end of the roof of the lower hearth exposed, the latter being connected at its unexposed end with the discharge end of the upper hearth, feed devices for discharging the material to be calcined upon the exposed portion of the roof or upper wall of the said lower hearth, whereby said material is primarily heated in the open air to be dried, plowing or agitating devices, means for moving the said devices through the hearth from the one to the other, a tirebox at the entrance end of the upper hearth, a fire-box in the lower hearth near the connection between the upper and lowerhearths, and a receptacle for the calcined material, such receptacle being below the lower hearth at the end upon which the material is fed.

NV. H. GODFREY. HENRY L. SHERLICK. 

